1. Field of the Invention
The present invention relates in general to a plant and a method for carrying out orderly arrangement of products in ranks along a packaging line.
In particular, the invention relates to packaging systems in which the products are arranged on a first conveyor belt according to ranks having substantially disorderly transverse alignment and with longitudinal distances that may vary between said ranks. From this first conveyor belt, the ranks must be transferred onto a second conveyor belt according to orderly ranks in a transverse direction and must be spaced longitudinally at pre-set distances.
2. Discussion of Related Art
The term xe2x80x9clongitudinalxe2x80x9d is meant, here and as follows, the direction parallel to the direction of advance of the conveyor belts. The term xe2x80x9ctransversexe2x80x9d is meant, here and as follows, the direction perpendicular to the longitudinal one.
A possible example of non-limiting application of the present invention is that of plants for packaging baked products coming from an oven in the foodstuff industry. The conditions of feed in ranks occur, in fact, downstream of an oven for the baking of foodstuff products, such as small cakes, tarts or the like, in which the-products at output from the oven are deposited according to irregular ranks on a conveyor belt for the subsequent steps of selection and packaging. Prior to the packaging step, the products must in any case arrive aligned in regular ranks and must be spaced at equal pre-set distances.
To obtain alignment of the products in ranks, as well as the right spacing as required, it is known to cause the products, which are possibly pre-selected, to advance in disorderly ranks up to a pair of conveyor belts, with the upstream conveyor belt operating in an intermittent or in a continuous way, and the downstream conveyor bell generally operating in a continuous way. At each rank of products which is transferred from the upstream conveyor belt to the conveyor belt immediately following it, a transverse blade drops down and temporarily stops the products until a rank is obtained that is perfectly aligned and spaced from a rank already present on the same downstream belt.
It is evident that this type of solution does not enable high rates of production to be sustained. This drawback is even more important in the cases where, according to the type and dimensions of the products, the orderly ranks must be spaced at intervals from one another at a considerable distance.
In general, one aspect of the present invention to provide a plant and a method that enable orderly arrangement of products in ranks along a packaging line to be carried out in an extremely fast way. Another aspect of the present invention is to provide a plant and a method such as the ones cited above, which enable a high productivity to be sustained irrespective of the distance that it is desired to obtain between the ranks of the products.
These aspects are achieved by the present invention, which relates to a plant for carrying out orderly arrangement of products along a packaging line, of the type comprising at least one alignment device arranged along the packaging line, and wherein the packaging line comprises at least one first conveyor belt, arranged upstream of the at least one alignment device, on which the products are set in ranks with substantially disorderly transverse alignment and with longitudinal distances that may vary between the ranks themselves, and at least one second conveyor belt, arranged downstream of the at least one alignment device, on which the products must be set aligned according to orderly ranks spaced at pre-set distances, characterized in that the alignment device comprises means for accelerating the ranks of products during their passage from the first conveyor belt to the second conveyor belt.
In this way it is possible to obtain alignment of the products in orderly ranks and proper spacing thereof without affecting the rate of arrival of the ranks at the alignment device, or in other words, irrespective of the rate of production.
The means for accelerating the ranks of products comprise one or more blades set in motion along at least one respective pre circuit by means of a motor driven in a controlled way. Each blade, while accelerating a rank, also aligns the products of the rank itself and accompanies them on the second conveyor belt.
The second conveyor belt is driven in motion at a higher speed than the first belt. By varying the speed between the conveyor belts, it is thus possible to obtain proper spacing between successive ranks of products.
According to a possible embodiment of the present invention, the means for accelerating the ranks of products comprise one or more distinct circuits, on each of which at least two blades are set in motion. The blades of one circuit are preferably set in motion by a motor controlled independently of the motor associated to another of said circuits.
In this way, at least one blade along one of the two circuits is always ready to intervene for carrying out alignment of a rank that is arriving at the alignment device when a blade associated with the other of he two circuits is carrying out alignment of a rank that arrived at an immediately preceding instant.
Each plant may of course be equipped also with two or more alignment devices, each set between consecutive conveyor belts, which are driven at different speeds. This allows to space ranks at increasing distances until, for example, a desired particularly long interval is obtained between one rank and the next, or else intervals that are in any case more reduced can be obtained without having to force the acceleration of the products during the subsequent steps of alignment/spacing.
The invention also relates to a method for carrying cut orderly arrangement of products along a packaging line by means of at least one alignment device arranged along the packaging tine, wherein the packaging line comprises at least one first conveyor belt, arranged upstream of the above-mentioned at least one alignment device, on which the products are set in ranks with substantially disorderly transverse alignment and with longitudinal distances that may vary between the ranks, and at least one second conveyor belt, arranged downstream of the at least one alignment device, on which the products must be set aligned according to orderly ranks spaced from one another at pre-set distances, characterized by providing acceleration of the ranks of products during their passage from the first conveyor belt to the second conveyor belt.
The method envisages, in particular, that a blade associated with one of the circuits will be stationary in a stop position, waiting to be operated in order to accelerate at least one rank of products. When a blade is moved from the stop position for alignment and acceleration of the ranks towards the second conveyor belt, at least one other blade associated to the other of the two circuits is shifted into the stop position. In this way it is always possible to intervene for aligning an immediately subsequent rank.
A blade is moved from the stop position when a distance is detected that is equal to or greater than a pre-set distance between two adjacent ranks on the first conveyor belt, Moreover, a blade is moved from the stop position when there is detected a longitudinal dimension of a rank equal to or smaller than a pre-set length.
It is thus possible to select the ranks that may be properly aligned and space them from those that are, instead, so disorderly as not to enable intervention of the alignment device. The detection of such events is then used for directing in the direction of a separate conveying line the ranks that have not been aligned and spaced.